RSA Key Pair Generation

The RSA cryptosystem was one of the first proposed and remains one of the most-used, public-key cryptosystems today. It’s named after the three researchers, Ron Rivest, Adi Shamir, and Len Adleman, who first published the idea. RSA is surprisingly straightforward to understand once the simple mathematics behind it are grasped.

Setting up RSA

All the real work in RSA occurs during key generation. This shouldn’t be surprising since the ‘clever’ part of any public-key cryptosystem is designing a relationship between two keys that allows one to reverse the effect of the other while allowing one of them to be publicly known. Note that we do not have to be quite so mathematically clever when generating symmetric keys, which just requires an ability to generate numbers randomly. The wider issues associated with key generation are discussed below.

Generating an RSA key pair

We are now ready to generate an RSA key pair. RSA key pairs can be generated for individuals or a key center may generate key pairs on behalf of a client. If we wish to set up a network of users who want to communicate with one another using RSA, then every user in the network will need to run this key pair generation process or have the trusted key center run it for them.